First principles study the influence of copper-vacancy on electronic, mechanical and thermal properties of CuGaTe2

Abstract

The influence of vacancy on electronic, mechanical and thermal properties of CuGaTe2 are investigated by first-principle calculations. The calculated formation energies are found to be lowest for vacancy at Cu site. The electronic properties display the energy gap, effective mass and density of states for CuGaTe2 with Cu vacancy at the Fermi energy level are increased. The results of elastic constants show that CuGaTe2 with Cu vacancy is mechanical stability. Based on the calculated elastic constants, the bulk modulus, shear modulus, sound velocities, Grünesian parameter and Debye temperature are estimated. By combining these calculated results and few well established models, low thermal conductivity is predicted. The analytical calculations reveal the reduction of Cu can effectively reduce the thermal conductivity, which may be the one way to enhance the thermoelectric properties of CuGaTe2.